Electrets and compounds useful in electrets

Abstract

An electret filter media that includes a thermoplastic resin and a compound of the formula Y 2 -A(R 1 ) n —Y 1 , where A is benzene, naphthalene or anthracene, Y 1 and Y 2 are each independently R 2 -R 3 , R 2 is an ester linking group or an amide linking group, R 3 is an alkyl group having from 10 to 22 carbon atoms, R 1 is R 2 -R 3 where R 2 and R 3 are each independently as defined above, and when A is benzene, n is from 0 to 4, when A is naphthalene, n is from 0 to 6, and when A is anthracene, n is from 0 to 8.

1. An electret filter media comprising a fibrous web that comprises fibers comprising:
 thermoplastic resin, and 
 a compound of the formula
   Y 2 -A(R 1 ) n —Y 1   (I) 
 
 where A is benzene, naphthalene or anthracene, 
 Y 1  and Y 2  are each independently R 2 -R 3 , 
 R 2  is an ester linking group or an amide linking group, 
 R 3  is a straight chain alkyl group having from 10 to 22 carbon atoms, 
 R 1  is R 2 -R 3 , where R 2  and R 3  are each independently as defined above, and 
 when A is benzene, n is from 0 to 4, 
 when A is naphthalene, n is from 0 to 6, and 
 when A is anthracene, n is from 0 to 8. 
 
   
   
     2. The electret filter media of  claim 1 , wherein A is benzene. 
   
   
     3. The electret filter media of  claim 2 , wherein R 2  is —CONH, —NHCO, —OCO or —COO. 
   
   
     4. The electret filter media of  claim 3 , wherein R 3  is an alkyl group having from 12 to 22 carbon atoms. 
   
   
     5. The electret filter media of  claim 3 , wherein n is 1. 
   
   
     6. The electret filter media of  claim 3 , wherein n is 1, and R 1 , Y 1  and Y 2  are located meta to each other. 
   
   
     7. The electret filter media of  claim 3 , wherein n is 0 and Y 1  and Y 2  are located para to each other. 
   
   
     8. The electret filter media of  claim 1 , wherein A is naphthalene. 
   
   
     9. The electret filter media of  claim 8 , wherein R 2  is —CONH—, —NHCO—, —OCO— or —COO—. 
   
   
     10. The electret filter media of  claim 8 , wherein R 3  is an alkyl group having from 12 to 22 carbon atoms. 
   
   
     11. The electret filter media of  claim 8 , wherein n is 0, Y 1  is located at the 2 position on naphthalene, and Y 2  is located at the 6 position on naphthalene. 
   
   
     12. The electret filter media of  claim 8 , wherein n is 1. 
   
   
     13. The electret filter media of  claim 1 , wherein the compound of formula (I) is selected from the group consisting of:
 benzene-1,3,5-tricarboxylic acid tris-octadecylamide; 
 p-phenylene distearylamide; 
 distearyl-2,6-naphthalenedicarboyxlate; and 
 2,6-naphthalene distearamide. 
 
   
   
     14. The electret filter media of  claim 1 , wherein the thermoplastic resin is selected from the group consisting of polycarbonate, polyolefin, polyester, halogenated polyvinyl, polystyrene, or a combination thereof. 
   
   
     15. The electret filter media of  claim 1 , wherein the thermoplastic resin is selected from the group consisting of polypropylene, poly-(4-methyl-1-pentene), or a combination thereof. 
   
   
     16. The electret filter media of  claim 1 , wherein the fibers include meltblown microfibers. 
   
   
     17. An air filter that comprises the electret filter media of  claim 1 . 
   
   
     18. A respirator that comprises at least one layer of filter media that includes the electret filter media of  claim 1 . 
   
   
     19. A vehicle ventilation system that comprises at least one layer of filter media that includes the electret filter media of  claim 1 .